Coumarin derivatives having optical whitening properties



United States Patent Oflice Patented Aug. 25, 1970 US. Cl. 260-6431 4Claims ABSTRACT OF THE DISCLOSURE New coumarin derivatives useful asoptical whitening agents and their use in the treatment of textilematerials. The coumarin derivatives are compounds of the formula Q o- ONwherein R is a hydrogen atom or alkyl group contain ing 1-4 carbon atomsand R is an alkyl group containing from 1 to 4 carbon atoms.

This invention is concerned with new chemical compounds of use asoptical whitening agents es ecially in the whitening and/or brighteningof polyamide, polyester and other synthetic fibres.

Optical whitening agents have in recent years found extensive use in thetreatment of textile fibres, both in their preparation and duringwashing, and are designed in general to counteract the yellow oroil-white colour which white textiles may develop. Such opticalwhitening agents also tend to improve coloured textiles as they impart ageneral brightness to them.

The present invention is based upon the discovery of certain coumarinderivatives which have particularly advantageous properties as opticalwhitening agents.

According to the present invention, there are provided compounds of thegeneral formula:

wherein R represents a hydrogen atom or an alkyl group which is ifdesired substituted by a non-ionogenic and non-colour producingsubstituent; and

R represents an alkyl group which is if desired substituted by anon-ionogenic and non-colour producing substituent.

As stated above, the compounds according to the invention haveparticularly advantageous properties as optieal whitening agents. Inparticular, they have excellent brightening properties for polyamide,polyester and other synthetic fibres when applied from aqueous andaqueous detergent baths, and have especially favourable fluorescentproperties with a most desirable shade of blue-violet fluorescence.

In compounds of Formula I in which R and/or R represents a substitutedor unsubstituted alkyl group, the said alkyl group preferably containsfrom 1 to 4 carbon atoms and is advantageously a methyl, ethyl, orisopropyl group. When R represents a substituted alkyl group, thesubstituent may for example be a halogen e.g. chlorine atom; R may thusrepresent a fi-chloroethoxy group. Alternatively, the substituent may bea radical of formula -NR R in which R, and R represent alkyl groups,preferably such groups containing from 1 to 14 carbon atoms; R may thusrepresent a group of formula --(CH ),,NR R wherein n represents aninteger from 1 to 4. Quaternised derivatives of such compounds are alsocompounds in accordance with the present invention. An especiallypreferred compound of Formula I is the compound in which R represents ahydrogen atom and R represents a methyl group.

For the purpose of treating textile fibres in general, the compoundsaccording to the invention may be advantageously be incorporated intocompositions comprising at least one compound of Formula I together witha solid or liquid carrier. Such compositions may for example be adaptedfor use in the washing of finished polyamide and polyester fibres, andcan take of the form of solutions suspensions and dispersions ofcompounds of Formula I in appropriate liquid carriers such as forexample, sulpholane, dimethylformamide and dimethylsulphoxide. Whendispersions are used, they conveniently include dispersing agents suchas for example alkyl naphthalen sulphonates. Aqueous compositions may ifdesired also contain for example synthetic detergents, soaps or surfaceactive agents. Alternatively the compositions may be solid form andcomprise at least one compound according to the invention together witha solid synthetic detergent or soap as carrier. The compounds of FormulaI may also be employed in the manufacture of synthetic fibres, e.g. byaddition to compositions from which the fibres are prepared by spinningor extrusion,

The coumarin derivatives of Formula I may be prepared by any convenientmethod, but are advantageously prepared by one of the followingprocesses:

(1) Reaction of a compound of formula Iii (wherein R is as defined aboveand X represents a cyano group or a group such as for example a nitrogroup convertible to a cyano group) with an approrpiate alkylating to acyano group. The alkylating agent is conveniently a dialkyl sulfate(e.g. dimethyl or diethyl sulphate) or an alkyl iodide (e.g. methyliodide or ethyl iodide). The compounds of Formula II used as startingmaterial in the reaction can for example first be prepared as follows:

(a) Reaction of a compound of formula OH HO- 3 (c) Where R represents ahydrogen atom, heating of c (4' cyanophenyl) ,8 (2",4" dimethoxyphenyl)acrylonitrile in the presence of an anhydrous Friedel- Crafts catalystsuch as for example aluminium chloride. The a (4' cyanophenyl) B (2",4"dimethoxyphenyl) acrylonitrile may if desired first be prepared by thereaction of p-cyanobenzyl cyanide with 2,4-dimethoxybenzaldehyde.

(2) Reaction of a compound of formula R20 /OH O I ll (wherein R and Rare as defined above) with a compound of formula (wherein X represents acyano group or a group such as for example a nitro group convertible toa cyano group) or a functional derivative thereof, and where necessaryconverting the group X to a cyano group.

-(3) Reaction of a coumarin derivative of formula (wherein R and R areas defined above) with a diazonium compound of formula (wherein Xrepresents a cyano group or a group such as for example a nitro groupconvertible to a cyano group), and where necessary converting the groupX to a cyano group.

Where R represents a hydrogen atom, the compounds of Formulae III andVII are substituted benzaldehydes. 2,4-dihydroxybenzaldehyde (FormulaIII, R =H) may thus for example be used.

Alternatively compounds of Formula VII such as for example 2 hydroxy 4methoxybenzaldehyde may be used which upon reaction with4-cyanophenylacetic acid or a functional derivative thereof yielddirectly a compound of Formula I. Where compounds of Formula I areobtained in which R represents a group containing a tertiary aminoradical, the tertiary amino radical can if desired be quaternised, forexample by reaction with dimethyl sulphate, diethyl sulphate, methyliodide or ethyl iodide as quaternising agent.

In order that the invention may be well understood the followingexamples (in which all parts are by weight) are given by way ofillustration only:

(VII) (VIII) EXAMPLE 1 p-Aminobenzonitrile (4.2 pts.) in aqueoushydrochloric acid (18%) (50 pts.) was diazotised with sodium nitrite(2.5 pts.) in water (10 pts.) at 05 C. The diazo slurry was added to amixture of sodium acetate (11.4 pts.), 7-methoxy-coumarin (6.3 pts.),acetone (24 pts.) and cupric chloride (1.5 pts.) in water (5 pts.). Thetemperature of the mixture rose 20 C. and nitrogen was evolved. Themixture was heated to 30 C. and held at that temperature for 3 hours.The reaction mixture was then cooled, filtered and dried. Theprecipitate was recrystallised from aqueous acetone to yield a pale greypowder (4.4 pts.) of 3(4' cyanophenyl) 7 methoxy coumarin. E =1010 at348 m M.P 230-235" C.

4 EXAMPLE 2 p-Cyanobenzyl cyanide (142 pts.) and2,4-dimethoxybenzaldehyde (166 pts.) are dissolved in methanol (1600pts.), cooled to 50 C. and caustic soda solution (sp. gr. (7.5 pts.) areadded to the solution. a-(4'-cyanophenyl) 5 (2",4"dimethoxyphenyl)acrylonitrile immediately precipitates. The reactionmixture is cooled to room temperature and the precipitate is collected,washed with ethanol and dried. Yield 235 pts., M.P. 199-200 C.

a (4' cyanophenyl) B (2",4 dimethoxyphenyl) acrylonitrile (145 pts.) isrefluxed in o-dichlorobenzene (1200 pts.) with anhydrous aluminiumchloride (250 pts.) for 8 hours. The reaction mixture is then cooled,filtered and thoroughly washed with water. The crude product is thensteam distilled to remove o-dichlorobenzene. The product is thenfiltered, washed with water and dried. The product is 3 (4' cyanophenyl)7 hydroxy coumarin, yield pts., M.P. 315 C.

3 (4 cyanophenyl) 7 hydroxycou marin (135 pts.), anhydrous potassiumcarbonate (100 pts.), dimethyl sulphate (100 pts.), andmethylethylketone (2500 pts.) are refluxed for 9 hours. At the end ofthe reaction the solvent is distilled off and the residual solid boiledwith water (4000 pts.). The solid is then filtered and dried. The 3- (4'cyanophenyl) 7 methoxy coumarin thus obtained is recrystallised from 35%acetic acid. M.P. 230 C., E 1040 at 348 mg.

The following compounds have been prepared by a process analogous tothat described in Example 2:

C E 1 m n x 3-(4-cyanophenyl) -7-ethoxycoumarin 196-8 966 3503(4-cyanophenyl)-7-isopropoxy-coumarin 216-8 958 351 EXAMPLE 3 Aqueousbaths are prepared containing 0.1 g./ litre of 3 (4' cyanophenyl) 7methoxy coumarin, 3 (4'- cyanophenyl) 7 ethoxycoumarin and 3 (4cyanophenyl)-7-isopropoxycoumarin respectively.

In use terylene fabric is treated in the baths for /5 hour at the boil,the liquor ratio being 1:40. The terylene thus treated is subsequentlyrinsed and dried and is in the case of each of the baths much whiter andbrighter than prior to the treatment.

I claim: 1. A compound of the formula 0 R20 \C:O

1&1 I

References Cited UNITED STATES PATENTS 3,351,482 11/1967 Raue 260343.2XR

HENRY R. JILES, Primary Examiner J. M. FORD, Assistant Examiner U.S. Cl.X.R.

